The earliest definition of a cocktail so far identified appeared in 1806 in an edition of a Hudson New York publication called The Balance, and Columbian repository.

“A cock-tail,” the editor explained in response to a curious reader’s inquiry, “is a stimulating liquor, composed of spirits of any kind, sugar, water and bitters”.

Substitute ice for the water and add a twist of lemon, and essentially you have an old-fashioned – the drink which gave the glass its name.

American rye whiskey or bourbon seem to have become the standard spirits of choice for the old-fashioned in the course of the 19th century and throughout the 20th, but in the 21st century bartenders looking to reinvigorate the classics have found the elegant simplicity of the recipe fertile ground for the expression of their own individuality.

At present the rum old-fashioned is an especially fashionable version, and I dropped into the Island Shangri-La’s Lobster Bar and Grill to have a chat with bar manager Agung Prabowo about his particular spin on it.

At 3pm I was expecting the place to be relatively quiet, but not a bit of it. The Lobster Bar recently joined Drinks International’s annual league table of The World’s 50 Best Bars, at No 18, and barflies are slipping in early in the knowledge that by 5pm you can’t get a bar stool.

Zacapa’s old-fashioned, made with Ron Zacapa, orange and Angostura bitters, and orange and lemon zests, is the bar’s signature version, but Prabowo and his team are happy to make you one with the spirit of your choice.

Ron Zacapa, he says, has “has a nutty clove and vanilla flavour, and people like those elements. It’s very complex in terms of taste and aroma.

“But you can make an old-fashioned with almost any spirit – gin, whiskey, scotch, brandy, mezcal, tequila – but you need to adjust the proportion of the bitters. For mezcal or tequila you need probably need one drop rather than two,” says Prabowo.

“We have quite a big range of brown spirits, and anyone can choose whatever they like. People ask for rye, rum and bourbon old-fashioneds, of course. I was recently asked to make a genever old-fashioned from a Dutch gin.”

The rum old-fashioned is the popular choice, though, because, according to Prabowo, there are now many good premium rums on the market.

The old-fashioned belongs to the “muddled” family of cocktails, meaning the first step in making them is to “muddle” the bitters, sugar and lemon peel in the glass before adding the ice and spirit.

There is some controversy over whether additional fruit should be “muddled” for an authentic old-fashioned, a slice of orange and/or a maraschino cherry being favoured choices. Purists have long insisted otherwise.

In 1945 the widely syndicated American newspaper columnist Lucius Beebe recounted having made the embarrassing error of asking a bartender at Chicago’s Drake Hotel for an old-fashioned “without fruit”.

“I’ve built old-fashioned cocktails these 60 years,” retorted the bartender, “and I have never yet had the perverted nastiness of mind to put fruit in an old-fashioned. Get out, scram, go over to the Palmer House and drink.”

Prabowo is not a purist and there are a few twists – apart from the lemon – in his recipe.

“In a normal old-fashioned you only use Angostura bitters, but in this one I add both Angostura bitters and orange bitters – three drops of Angostura and two drops of orange. A classic old-fashioned is supposed to be made with a sugar cube. Here, I’m using a simple syrup because I want to make the drinks consistent. Sugar cubes can vary in size,” he explains.

As is the case with all classic cocktails, the secret of a successful old-fashioned is all to do with balance. If making the cocktail with spirits other than rum, Prabowo varies not only the quantities of bitters, but the length of time he stirs the drink, to produce a slight but significant difference in the level of dilution. A big, slow melting ice cube, he says, is essential. The Lobster Bar’s come stamped with its logo.

If he feels like an old-fashioned himself when off duty, Prabowo has a connoisseur’s list of bars he likes to go to.

“Stockton, The Envoy and the bar at Otto e Mezzo. And they do a very good rum old-fashioned at Honi Honi,” he says.